Nevertheless, recent reports have shown that the immune response activated by IFN-γ plays a dual role in cancer: It can not only suppress tumor growth by destroying cancer cells or inhibiting their outgrowth but also promote tumor progression either by selecting for tumor cells that are more fit to survive in an immunocompetent host or by establishing conditions within the tumor microenvironment that facilitate tumor outgrowth [48]. This evidence concerns the gene IFNG and cancer.